Finding the Main Idea 阅读：找出主旨
基础Main idea 是整段最想讲的东西——通常在 topic sentence，其他句子是支持细节。
- Main idea = 整段最想讲的东西，一句讲完就得
- Topic sentence 多数在段首；Unfortunately / However 这些转折词后面好重要
- Details 是支持证据：over 400 million years、500 species 这些数字不是主旨
文体小知识：Find the one sentence that rules the paragraph.
§课文原文 Passage
1Sharks have lived in the oceans for over 400 million years, which means they are older than the dinosaurs. There are more than 500 different species, and they live in every ocean in the world. Some sharks are longer than a bus, while others are smaller than your school ruler. Most sharks are harmless to humans because they eat fish, seals and squid. Only about 10 species are dangerous, and attacks are very rare.
2Unfortunately, people kill millions of sharks every year for their fins. Fishermen cut off the fins and throw the sharks back into the sea. This has caused many populations to drop, and some species may disappear completely. Scientists warn that losing sharks will damage the whole ocean ecosystem, because sharks keep the number of smaller fish under control. Without them, the balance of nature will be destroyed.
3The good news is that everyone can help. We can refuse to eat shark fin soup at banquets and weddings. We can support the shops and restaurants that protect sea life. Several countries have already banned shark fishing in their waters, and Hong Kong has joined an international agreement to protect shark species too. We should protect sharks because they are important for the ocean ecosystem, and a healthy ocean is important for us all.
§逐句中文翻译 Sentence-by-sentence translation
Sharks have lived in the oceans for over 400 million years, which means they are older than the dinosaurs.
鲨鱼在海洋里生活了超过四亿年，即是牠们比恐龙还古老。
There are more than 500 different species, and they live in every ocean in the world.
鲨鱼有超过五百个品种，在全世界每个海洋都找到牠们。
Some sharks are longer than a bus, while others are smaller than your school ruler.
有些鲨鱼比一架巴士还长，有些就比你的学校间尺还小。
Most sharks are harmless to humans because they eat fish, seals and squid.
大部分鲨鱼对人类无害，因为牠们吃鱼、海豹同鱿鱼。
Only about 10 species are dangerous, and attacks are very rare.
只有大约十个品种是危险的，而且袭击事件非常罕见。
Unfortunately, people kill millions of sharks every year for their fins.
可惜的是，人类每年为了鱼翅杀死几百万条鲨鱼。
Fishermen cut off the fins and throw the sharks back into the sea.
渔民割了鱼鳍，就把鲨鱼丢回海里。
This has caused many populations to drop, and some species may disappear completely.
这个情况令很多族群数量下跌，有些品种还可能完全消失。
Scientists warn that losing sharks will damage the whole ocean ecosystem, because sharks keep the number of smaller fish under control.
科学家警告，失去鲨鱼会破坏整个海洋生态系统，因为鲨鱼控制住小鱼的数量。
Without them, the balance of nature will be destroyed.
没有了牠们，大自然的平衡就会被摧毁。
The good news is that everyone can help.
好消息是，人人都可以出一分力。
We can refuse to eat shark fin soup at banquets and weddings.
我们可以在宴会同婚礼上拒绝吃鱼翅。
We can support the shops and restaurants that protect sea life.
我们可以支持一些保护海洋生物的商舖同餐厅。
Several countries have already banned shark fishing in their waters, and Hong Kong has joined an international agreement to protect shark species too.
有几个国家已经禁止在自己水域捕鲨，香港亦加入了保护鲨鱼品种的国际协议。
We should protect sharks because they are important for the ocean ecosystem, and a healthy ocean is important for us all.
我们应该保护鲨鱼，因为牠们对海洋生态很重要，而健康的海洋对我们所有人都很重要。
1重点摘要 Summary
Main idea 是整段最想讲的东西——通常在 topic sentence，其他句子是支持细节。
2生字卡 Vocabulary
文章主要讯息。
开头那句。
支持主旨的事实。
证明主旨。
短版。
几句组成一段。
阅读文章。
重要的字。
3逐步讲解 Steps
- 读首句主题句多数在段首：P0 第一句 Sharks have lived in the oceans for over 400 million years——立刻知道整段在讲鲨鱼历史悠久。段首句不一定第一句：有时例子之后先亮主旨——所以读埋段尾先好落判断。
- 找关键字重复出现的字就是线索：sharks、ocean、species 不断出现——主旨一定围著这几个字转。字数比例都是线索：哪个话题占最多句，主旨就偏那边——不妨数一数 sharks 出现了多少次。
- 归纳每段用一句讲完：P1 = 鲨鱼因为鱼翅给人大量捕杀。写 summary 时删走数字，留回立场。自己先讲一次再对选项：『这段是讲……』——你讲得出的，先算你归纳到的主旨。
- 分主旨细节数字是细节不是主旨：over 400 million years、500 species、only about 10 species dangerous——这些支持住 'Most sharks are harmless' 这个主旨。
- 转折词Unfortunately / However 后面好重要：Unfortunately, people kill millions of sharks for their fins——段的立场好大机会在转折词后面。转折词仲有 In fact / Actually——事实修正讯号：作者讲完一般讲法，跟住纠正——真意多数在后面。
- 雨伞测试主旨要盖住整段：'Sharks are old' 太窄；'The ocean is important' 太阔。对的是：We should protect sharks because they keep the ocean healthy.雨伞测试实操：把选项放进 The passage tells us that… 读一次——盖到全篇、不会太阔太窄的先选。
- 段落功能三段结构：P0 鲨鱼无害（破误解）→ P1 它们有危险（问题）→ P2 我们可以点帮（解决）。明白结构，主旨自然浮现。留意题目问一段定全文：main idea of paragraph 2 只看该段；the passage 就要盖住全文——范围错，答案实错。
4图解 Diagrams
5例题示范 Example
根据鲨鱼课文，第二段（人类猎杀鲨鱼那段）的 main idea 是什么？用一句完整英文讲出来。
- 第一步：读段首句——Unfortunately, people kill millions of sharks every year for their fins.
- 第二步：圈出重复关键字——sharks、kill、drop、disappear。
- 第三步：检查其他句子是不是支持第一句——数量跌、物种消失，全部是猎杀的后果。
- 第四步：做雨伞测试——你选的主旨要盖住段内所有 details。
- 第五步：用完整句作答——The main idea is that…
- 答案：The main idea is that people kill millions of sharks for their fins, and this is pushing many species towards extinction. 段首 Unfortunately… 这句就是 topic sentence；之后的句子（populations drop、species may disappear）全部是 details，用来支持它。答 main idea 题一句讲完就得，不用抄细节数字。
6常见错误 Mistakes
78 题快测 Quick check
Q1Which sentence is the main idea of paragraph 1?
Q2Where is the topic sentence?
Q3What supports the main idea?
Q4What is a short version called?
Q5What is a block of text called?
Q6What is the main idea?
Q7How many shark species are dangerous?
Q8What should we do?
8重点回顾 Recap
- Main idea = 整段最想讲的东西，一句讲完就得
- Topic sentence 多数在段首；Unfortunately / However 这些转折词后面好重要
- Details 是支持证据：over 400 million years、500 species 这些数字不是主旨
- 雨伞测试：主旨要盖住段内所有细节，太窄太阔都错
- 课文立场：鲨鱼维持海洋生态平衡——拒吃鱼翅、refuse shark fin soup